Revert "front: Apply gray action bar only to game activity."

This reverts commit 38f614f12bad26baa57cfa546a04b138277022e4.
Revert "res: change action bar background color"

This reverts commit 68910db16511342d5bd3da8523433471f387f136.
front: Added pref to change in-game action bar transparency.

Oh what the hell, it wasn't hard to add.
In the video settings, defaults to 50%.